1. Field of the Invention
This invention relates generally to gas-insulated switchgear equipment and, more particularly, to gas-insulated switchgear equipment constituted by connecting a plurality of vertical-type circuit breakers.
2. Description of the Prior Art
An example of conventional gas-insulated switchgear equipment of this type, such as the one shown in FIG. 10 on page 147 of BROWN BOVERI REV. vol. 4, No. 73 is known.
The gas-insulated switchgear equipment is called a one-and-a-half circuit breaker system and in the system, a pair of gas-insulated bus bars are disposed in parallel and three horizontal-type circuit breakers are horizontally disposed on a straight line bridging the pair of bus bars. The circuit breakers are connected in series by connecting bus bars disposed between the circuit breakers.
Since this type of gas-insulated switchgear equipment uses connecting bus bars which are disposed between the circuit breakers, a large fixing space for the equipment is needed in a straight line direction of the disposition of the circuit breakers.
Although the described example of a gas-insulated switchgear equipment is constructed by using horizontal-type circuit breakers, it is also possible to constitute the same gas-insulated switchgear equipment by using vertical-type circuit breakers. However, this method not only has the above-described problem but also needs to devise a disposition of the bus bars as well as connections between the circuit breakers and between the circuit breakers and the bus bars.
In view of these problems, gas-insulated switchgear equipment such as one-and-a-half circuit breaker systems and ring bus system using a plurality of vertical-type circuit breakers have been proposed in Japanese Patent Unexamined Publication Nos. 57-193911, 57-211915 (U.S. counterpart: U.S. Pat. No. 4,503,481), and 59-6706. In this equipment, a pair of main bus bars are disposed parallel to a fixing base and a plurality of vertical-type breakers are disposed at one side of the bus bars generally in parallel to the bus bars. Cable heads provided as outside led-out means are disposed at the other side of the main bus bar which is the most remote from the breakers. Gas-insulated connecting bus bars electrically connected between the juxtaposed circuit breakers, between the circuit breakers and the main bus bars and between the circuit breakers and the cable heads.
In the gas-insulated switchgear equipment, each of the vertical-type circuit breakers has led-out portions extending from its breaking section on the one side facing the main bus bars. Therefore, there is no element on the other side of each of the circuit breakers. This is advantageous in terms of inspection and maintenance of the circuit breakers. However, the equipment has disadvantages whereby the connecting structure using the connecting bus bars becomes complex and the fixing area to fix the equipment becomes when taking connecting operations into consideration.